Effect of Rates and Time of Paclobutrazol Application on Growth, Lodging, and Yield and Yield Components of Tef [Eragrostis Tef (Zucc.) Trotter] in Adadistrict, East Shewa, Ethiopia

In Ethiopia, tef is valuable crop to achieve national economic stability, and improved livelihood of many farmers. The objective of the present study was to assess the effects of rates and time of paclobutrazol (PBZ) application on growth, lodging, yield and yield components of tef. Twelve entire factorial combinations of three rates (0, 1, 2 and 3 kg a.i.) and three growth stages (i.e. tillering, jointing and panicle emergence) of application of PBZ were evaluated in a field experiment on the research field of Debre Zeit Agricultural Research Center using randomized complete block design with three replication during the 2016 main season. Data were collected on plant height, number of tillers (fertile, unfertile and total) per plant, panicle length, culm length, lengthof the upper three culm internodes, days to Panicle emergence and physiological maturity, thousand seed weight, lodging index, grain yield, biological yield ,straw yield, harvest index (HI) and crude protein. The data were subjected to statistical analysis using SAS and mean differences were compared using Duncan’s Multiple Range Test. The analysis of variance showed that time of application, PBZ rate, and the interaction of two had significant (P≤ 0.01) effect on all the characters except number of non fertile tiller and thousand seed weight. Spraying 1kg of PBZ at jointing stage could suppress vegetative growth and increased number of fertile tillers and grain yield and minimized the risk of lodging. Therefore, spraying 2kg a.i of PBZ ha-1at jointing stage can be suggested as effective to maximize grain yield of tef. Keywords: PBZ; Grain yield; Lodgin